Passive infra-red sensor



FIG. 1 is a side elevational view of a passive infra-red sensor, showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is an elevational view of the side opposite that shown in FIG. 1;

FIG. 6 is a top plan view thereof. 

The ornamental design for a passive infra-red sensor, as shown. 